correspondence chess in the age of NNUE

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Vinvin
Posts: 5009
Joined: Thu Mar 09, 2006 8:40 am
Full name: Vincent Lejeune

Re: correspondence chess in the age of NNUE

Post by Vinvin » Wed Feb 03, 2021 11:45 pm

Master Om wrote:
Sun Jan 31, 2021 5:08 pm
Check this position.

6rk/pp1bbr2/3p1n1q/PPpPp1pp/2P1Pp1n/R4P1P/4BNPN/1Q2BRK1 b - - 0 33

This is from my own game. This came out from a KID opening.
Just Check the eval here. Here my opponent who is an OTB GM played 33.Qb1
This is a corr game and u can see how helpless engines are here.

Now after deep analysis I found 33...Nxg2! can be played and then Bxh3!
But check the eval and the moves suggested...

6rk/pp1bbr2/3p1n1q/PPpPp1pp/2P1Pp1n/R4P1P/4BNPN/1Q2BRK1 b - - 0 33

33... Nxg2 34. Kxg2 Bxh3+ 35. Nxh3 g4 36. fxg4 hxg4 37. Bxg4 Nxg4 38. Kh1 Rfg7
39. Nxg4 Rxg4 40. Qd1 Qh7 41. Qe2 Bh4 42. Bxh4 Rxh4 43. Rff3 Qg6 44. Ra1 Qh6
45. Raa3 Qg6 46. Ra1 Rg7 47. Qf2 Qh7 48. Raa3 Kg8 49. Qe1 Kf7 50. Qf2 Rhg4 51.
Qe3 Ke7 52. Qe1 *

If Black gives up 2 rooks for the queen Nxf4!! after doubling of rooks in f file makes the game draw.
But engines dont get it.

Now after 33...Nfg7 34.Nfg4!! hxg4 35. fxg4 the position is interesting.
See how no engines show a valid way to play this position.
After Bxh4 and Bf3 there is no way for black to penetrate white's camp.
Here's the opinion (3 best moves) of Crystal3.1 about the position after 33... Rfg7 34. Nfg4 hxg4 35. fxg4
It likes Qg6 followed by f3

[d]6rk/pp1bb1r1/3p1n1q/PPpPp1p1/2P1PpPn/R6P/4B1PN/1Q2BRK1 b - - 0 35

Code: Select all

Crystal3.1-sse4-popcnt:
...
 29/48	04:03	1 311 698 851	5 378 724	-2,13	35. ... Qh7 36.Bxh4 Qxh4 37.Rf2 Ra8 38.Rf1 Bd8 39.Bf3 Nh7 40.Rf2 Qh6 41.Rfa2 Nf8 42.Ra1 Kg8 43.R1a2 Ng6 44.Kf2 Rb8 45.Kf1 Qh4 46.Ke2 Qh7 47.Ke1 Nh4 48.Kf1 Rf7 49.Qd3 Qh8 50.Qb1 Kg7 51.Qd3 Ng6 52.Qb1 Be7 53.Kg1 Bf6 54.Kf1 Nh4 55.Kf2 a6 56.b6
 29/52	04:03	1 311 698 851	5 378 724	-2,13	35. ... Ra8 36.Ra2 Bd8 37.Ra3 Ng6 38.Bf2 Qh7 39.Bf3 Nh4 40.Bxh4 Qxh4 41.Rf2 Nh7 42.Rf1 Nf8 43.Rf2 Ng6 44.Rfa2 Kg8 45.Rb2 Qh6 46.Rba2 Rb8 47.Kf1 Qh4 48.Ke2 Qh7 49.Ke1 Nh4 50.Kf1 Rf7 51.Qd3 Qh8 52.Qb1 Kg7 53.Qd3 Ng6 54.Qb1 Be7 55.Kg1 Bf6 56.Kf1 Nh4 57.Kf2 a6 58.b6
 29/47	04:03	1 311 698 851	5 378 724	-2,35	35. ... Qg6 36.Ra2 f3 37.Nxf3 Qxe4 38.Qxe4 Nxe4 39.Nh2 Ng6 40.g3 Nf6 41.Bc3 Rf8 42.Nf3 Kg8 43.Kg2 Bd8 44.Bb2 Nh8 45.a6 b6 46.Nd2 e4 47.Ra3 Rgf7 48.Rb3 Re8 49.Re3 Rff8 50.Bd1 Ng6 51.Bc2 Ne5 52.Ba1 Re7 53.Bb2 Be8 54.Bxe5 Rxe5

jefk
Posts: 533
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Location: the Netherlands
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Re: correspondence chess in the age of NNUE

Post by jefk » Thu Feb 04, 2021 11:33 am

Mike, 'mbabigan'

about the wall of text, yep was in writing mood, and |
probably overreacted (you're right i should consider upgrading
my machine, in May here we get 'holiday' money added to
the allowance (which i get besides a little pension) and then
i consider a refurbished server or so. The point i was trying to
make is that you may have a fast machine, but it's also
still important how to use it. For some reason, although
alfa/beta is scientifically correct, SF tends to discard
'positional' moves which sometimes popup with other engines
(as maybe in Komodo Dragon, Mcts or so); but then, when i
analyze as centaur with different engines, speed/ nr of cpu's
would help as well of-course (a lot, in fact, indeed).
NB i considered editing/shortening my 'wall of text' (i'm a writer
you know'), but after a few hours on this system, you can't edit it
anymore (if there would be an option to delete your earlier mail, i would
welcome it (tip to moderators); in such a case i can copy
my earlier text, delete the post, edit it offline , and re-post it later.
Anyway i'll accept your 'peace proposal' of-course ;) (some yanks ,
drunk Brits, and/or chess players tend to have a rather direct
way of communicating btw, and as Dutchman it's the same , or
similar for me sometimes, not wanting to be belligerent (more like assertive/defensive), but just trying to be honest (but then things
often are subjective anyway i've noticed during the year (so also
for me i must admit). anyway i hoped you (or some others maybe)
enjoyed my little rant about Otb psycho kid chess players :)
Best of luck avoiding the draw against MonteCarlo and his "fast" machine. It likely won't be easy.
yep thx, i'm certain that i will get a slight advantage in the endgame
but then it may still become a draw (depending on which engine (*) MC is using,
with current rules and high drawing margin. Cheers as well :)
(*) SF may have Nnue nowadays, but it's not perfect yet imho

PS as for my 'novelty' (wrt to the Aronian game in 2011 with the awesome
Nd2 move ), i would play 13.b4!N instead of his 13.Nh3?!
but whether i will go for the Nd2 move, remains to be seen
(at least i now have the option open, after this (SF?) 1...Nf6?! move..
:)

"write drunk, edit sober" (E.Hemingway)
jefk

mbabigian
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Location: US
Full name: Mike Babigian

Re: correspondence chess in the age of NNUE

Post by mbabigian » Thu Feb 04, 2021 6:25 pm

jefk, you hit the nail on the head. I have a very direct communication style, with a poke fun at everything personality/sense of humor. I don't drink so i can't offer that defense, but hope you know I'm only pulling your leg a bit.

I also agree that it isn't about the speed of the hardware, but knowing how to leverage the software. I know many chess players and not one of them understands how to use chess engines for serious analysis or correspondence chess (many/most of them think they do).

Understanding how the software works is a huge advantage (I'm a programmer). Leela is much stronger in the opening than SF for example, but leela is worthless without the nibbler gui. And the list goes on for SF, SF clones with fortress detection, utilizing large hash, etc.

I thought about offering to comment on your game's past moves, but i don't want to sway the results or offend your opponent.

Winning a long match against MonteCarlo for a talented correspondence player should be easy, avoiding a draw in a single game, not so much.

You have your work cut out for you.
“Censorship is telling a man he can't have a steak just because a baby can't chew it.” ― Mark Twain

MonteCarlo
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Joined: Sun Dec 25, 2016 3:59 pm

Re: correspondence chess in the age of NNUE

Post by MonteCarlo » Thu Feb 04, 2021 8:02 pm

mbabigian wrote:
Thu Feb 04, 2021 6:25 pm
...or offend your opponent.
No worries on that front. I'm not so easily offended, and strictly speaking I'm not even his opponent, just a middleman relaying moves :D
mbabigian wrote:
Thu Feb 04, 2021 6:25 pm
Winning a long match against MonteCarlo for a talented correspondence player should be easy, avoiding a draw in a single game, not so much.
Agreed. Especially with the effective time odds I think the unassisted engine is bound to lose in a match, and probably even without the time odds

One game, with no history to help predict what this HW/SW/config will play, is probably much more difficult to win.

Just a few years ago I'd be pretty certain of the engine losing in these conditions. Now I think it's interesting.

We shall see...

Cheers!

jefk
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Re: correspondence chess in the age of NNUE

Post by jefk » Fri Feb 05, 2021 1:20 pm

well i don't know if i could win a long match against MC
with the same conditions, and certainly not if he would
learn from the previous games.

The current test game btw is not as result of a challenge
by MC, it's a result of a question posted by 'Carldaman'
(in the thread purpose of correspondence chess :
Can a test be run to see if top human corr players (playing as centaurs) can defeat unaided top engines running on some 'regular' hardware?"
After which i proposed to run a testgame (with some more specific
conditions); this challenge was subsequently accepted by 'montecarlo'
(instead of 'carldaman').

For the rest i also assume MC won't change his engine during the game
(as for fortress detection, hmm well that won't help if i would
be able to continuously/gradually build up a slight advantage
to a decisive advantage. And as i said, mainly to show
some inherent White advantage, but not to demonstrate
that correspondence chess still has a long way to go
with current rules (i also think it doesn't, and in next Iccf
WC finals i expect the nr of (White) wins will go down, after
which the ICCF will also start to recognize the draw problem...

PS i've posted my 3rd move, as you can see in the 'matches' thread
(now expecting ...d5 or Bb4, possibly Be7 (*), we'll see :)
jefk

MonteCarlo
Posts: 152
Joined: Sun Dec 25, 2016 3:59 pm

Re: correspondence chess in the age of NNUE

Post by MonteCarlo » Fri Feb 05, 2021 1:45 pm

jefk wrote:
Fri Feb 05, 2021 1:20 pm
For the rest i also assume MC won't change his engine during the game
Indeed. I will be using the same HW/SW/config the entire game.

Cheers!

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Master Om
Posts: 436
Joined: Wed Nov 24, 2010 9:57 am
Location: INDIA

Re: correspondence chess in the age of NNUE

Post by Master Om » Mon Feb 08, 2021 4:17 pm

Vinvin wrote:
Wed Feb 03, 2021 11:45 pm
Master Om wrote:
Sun Jan 31, 2021 5:08 pm
Check this position.

6rk/pp1bbr2/3p1n1q/PPpPp1pp/2P1Pp1n/R4P1P/4BNPN/1Q2BRK1 b - - 0 33

This is from my own game. This came out from a KID opening.
Just Check the eval here. Here my opponent who is an OTB GM played 33.Qb1
This is a corr game and u can see how helpless engines are here.

Now after deep analysis I found 33...Nxg2! can be played and then Bxh3!
But check the eval and the moves suggested...

6rk/pp1bbr2/3p1n1q/PPpPp1pp/2P1Pp1n/R4P1P/4BNPN/1Q2BRK1 b - - 0 33

33... Nxg2 34. Kxg2 Bxh3+ 35. Nxh3 g4 36. fxg4 hxg4 37. Bxg4 Nxg4 38. Kh1 Rfg7
39. Nxg4 Rxg4 40. Qd1 Qh7 41. Qe2 Bh4 42. Bxh4 Rxh4 43. Rff3 Qg6 44. Ra1 Qh6
45. Raa3 Qg6 46. Ra1 Rg7 47. Qf2 Qh7 48. Raa3 Kg8 49. Qe1 Kf7 50. Qf2 Rhg4 51.
Qe3 Ke7 52. Qe1 *

If Black gives up 2 rooks for the queen Nxf4!! after doubling of rooks in f file makes the game draw.
But engines dont get it.

Now after 33...Nfg7 34.Nfg4!! hxg4 35. fxg4 the position is interesting.
See how no engines show a valid way to play this position.
After Bxh4 and Bf3 there is no way for black to penetrate white's camp.
Here's the opinion (3 best moves) of Crystal3.1 about the position after 33... Rfg7 34. Nfg4 hxg4 35. fxg4
It likes Qg6 followed by f3

[d]6rk/pp1bb1r1/3p1n1q/PPpPp1p1/2P1PpPn/R6P/4B1PN/1Q2BRK1 b - - 0 35

Code: Select all

Crystal3.1-sse4-popcnt:
...
 29/48	04:03	1 311 698 851	5 378 724	-2,13	35. ... Qh7 36.Bxh4 Qxh4 37.Rf2 Ra8 38.Rf1 Bd8 39.Bf3 Nh7 40.Rf2 Qh6 41.Rfa2 Nf8 42.Ra1 Kg8 43.R1a2 Ng6 44.Kf2 Rb8 45.Kf1 Qh4 46.Ke2 Qh7 47.Ke1 Nh4 48.Kf1 Rf7 49.Qd3 Qh8 50.Qb1 Kg7 51.Qd3 Ng6 52.Qb1 Be7 53.Kg1 Bf6 54.Kf1 Nh4 55.Kf2 a6 56.b6
 29/52	04:03	1 311 698 851	5 378 724	-2,13	35. ... Ra8 36.Ra2 Bd8 37.Ra3 Ng6 38.Bf2 Qh7 39.Bf3 Nh4 40.Bxh4 Qxh4 41.Rf2 Nh7 42.Rf1 Nf8 43.Rf2 Ng6 44.Rfa2 Kg8 45.Rb2 Qh6 46.Rba2 Rb8 47.Kf1 Qh4 48.Ke2 Qh7 49.Ke1 Nh4 50.Kf1 Rf7 51.Qd3 Qh8 52.Qb1 Kg7 53.Qd3 Ng6 54.Qb1 Be7 55.Kg1 Bf6 56.Kf1 Nh4 57.Kf2 a6 58.b6
 29/47	04:03	1 311 698 851	5 378 724	-2,35	35. ... Qg6 36.Ra2 f3 37.Nxf3 Qxe4 38.Qxe4 Nxe4 39.Nh2 Ng6 40.g3 Nf6 41.Bc3 Rf8 42.Nf3 Kg8 43.Kg2 Bd8 44.Bb2 Nh8 45.a6 b6 46.Nd2 e4 47.Ra3 Rgf7 48.Rb3 Re8 49.Re3 Rff8 50.Bd1 Ng6 51.Bc2 Ne5 52.Ba1 Re7 53.Bb2 Be8 54.Bxe5 Rxe5
Here's the opinion (3 best moves) of Crystal3.1 about the position after 33... Rfg7 34. Nfg4 hxg4 35. fxg4
It likes Qg6 followed by f3
After Qg6 there will be Bxh4!. Now gxh4 seals the position.
Always Expect the Unexpected

Vinvin
Posts: 5009
Joined: Thu Mar 09, 2006 8:40 am
Full name: Vincent Lejeune

Re: correspondence chess in the age of NNUE

Post by Vinvin » Mon Feb 08, 2021 7:42 pm

Master Om wrote:
Mon Feb 08, 2021 4:17 pm
Vinvin wrote:
Wed Feb 03, 2021 11:45 pm
Here's the opinion (3 best moves) of Crystal3.1 about the position after 33... Rfg7 34. Nfg4 hxg4 35. fxg4
It likes Qg6 followed by f3

[d]6rk/pp1bb1r1/3p1n1q/PPpPp1p1/2P1PpPn/R6P/4B1PN/1Q2BRK1 b - - 0 35

Code: Select all

Crystal3.1-sse4-popcnt:
...
 29/48	04:03	1 311 698 851	5 378 724	-2,13	35. ... Qh7 36.Bxh4 Qxh4 37.Rf2 Ra8 38.Rf1 Bd8 39.Bf3 Nh7 40.Rf2 Qh6 41.Rfa2 Nf8 42.Ra1 Kg8 43.R1a2 Ng6 44.Kf2 Rb8 45.Kf1 Qh4 46.Ke2 Qh7 47.Ke1 Nh4 48.Kf1 Rf7 49.Qd3 Qh8 50.Qb1 Kg7 51.Qd3 Ng6 52.Qb1 Be7 53.Kg1 Bf6 54.Kf1 Nh4 55.Kf2 a6 56.b6
 29/52	04:03	1 311 698 851	5 378 724	-2,13	35. ... Ra8 36.Ra2 Bd8 37.Ra3 Ng6 38.Bf2 Qh7 39.Bf3 Nh4 40.Bxh4 Qxh4 41.Rf2 Nh7 42.Rf1 Nf8 43.Rf2 Ng6 44.Rfa2 Kg8 45.Rb2 Qh6 46.Rba2 Rb8 47.Kf1 Qh4 48.Ke2 Qh7 49.Ke1 Nh4 50.Kf1 Rf7 51.Qd3 Qh8 52.Qb1 Kg7 53.Qd3 Ng6 54.Qb1 Be7 55.Kg1 Bf6 56.Kf1 Nh4 57.Kf2 a6 58.b6
 29/47	04:03	1 311 698 851	5 378 724	-2,35	35. ... Qg6 36.Ra2 f3 37.Nxf3 Qxe4 38.Qxe4 Nxe4 39.Nh2 Ng6 40.g3 Nf6 41.Bc3 Rf8 42.Nf3 Kg8 43.Kg2 Bd8 44.Bb2 Nh8 45.a6 b6 46.Nd2 e4 47.Ra3 Rgf7 48.Rb3 Re8 49.Re3 Rff8 50.Bd1 Ng6 51.Bc2 Ne5 52.Ba1 Re7 53.Bb2 Be8 54.Bxe5 Rxe5
Here's the opinion (3 best moves) of Crystal3.1 about the position after 33... Rfg7 34. Nfg4 hxg4 35. fxg4
It likes Qg6 followed by f3
After Qg6 there will be Bxh4!. Now gxh4 seals the position.
After 35... Qg6 36. Bxh4, Crystal3.1 wants to play : f3 37. Nxf3 gxh4 38. Nxh4 Qxe4 39. Qxe4 Nxe4 with an eval around -2

User avatar
Master Om
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Location: INDIA

Re: correspondence chess in the age of NNUE

Post by Master Om » Thu Feb 11, 2021 3:06 pm

Vinvin wrote:
Mon Feb 08, 2021 7:42 pm
Master Om wrote:
Mon Feb 08, 2021 4:17 pm
Vinvin wrote:
Wed Feb 03, 2021 11:45 pm
Here's the opinion (3 best moves) of Crystal3.1 about the position after 33... Rfg7 34. Nfg4 hxg4 35. fxg4
It likes Qg6 followed by f3

[d]6rk/pp1bb1r1/3p1n1q/PPpPp1p1/2P1PpPn/R6P/4B1PN/1Q2BRK1 b - - 0 35

Code: Select all

Crystal3.1-sse4-popcnt:
...
 29/48	04:03	1 311 698 851	5 378 724	-2,13	35. ... Qh7 36.Bxh4 Qxh4 37.Rf2 Ra8 38.Rf1 Bd8 39.Bf3 Nh7 40.Rf2 Qh6 41.Rfa2 Nf8 42.Ra1 Kg8 43.R1a2 Ng6 44.Kf2 Rb8 45.Kf1 Qh4 46.Ke2 Qh7 47.Ke1 Nh4 48.Kf1 Rf7 49.Qd3 Qh8 50.Qb1 Kg7 51.Qd3 Ng6 52.Qb1 Be7 53.Kg1 Bf6 54.Kf1 Nh4 55.Kf2 a6 56.b6
 29/52	04:03	1 311 698 851	5 378 724	-2,13	35. ... Ra8 36.Ra2 Bd8 37.Ra3 Ng6 38.Bf2 Qh7 39.Bf3 Nh4 40.Bxh4 Qxh4 41.Rf2 Nh7 42.Rf1 Nf8 43.Rf2 Ng6 44.Rfa2 Kg8 45.Rb2 Qh6 46.Rba2 Rb8 47.Kf1 Qh4 48.Ke2 Qh7 49.Ke1 Nh4 50.Kf1 Rf7 51.Qd3 Qh8 52.Qb1 Kg7 53.Qd3 Ng6 54.Qb1 Be7 55.Kg1 Bf6 56.Kf1 Nh4 57.Kf2 a6 58.b6
 29/47	04:03	1 311 698 851	5 378 724	-2,35	35. ... Qg6 36.Ra2 f3 37.Nxf3 Qxe4 38.Qxe4 Nxe4 39.Nh2 Ng6 40.g3 Nf6 41.Bc3 Rf8 42.Nf3 Kg8 43.Kg2 Bd8 44.Bb2 Nh8 45.a6 b6 46.Nd2 e4 47.Ra3 Rgf7 48.Rb3 Re8 49.Re3 Rff8 50.Bd1 Ng6 51.Bc2 Ne5 52.Ba1 Re7 53.Bb2 Be8 54.Bxe5 Rxe5
Here's the opinion (3 best moves) of Crystal3.1 about the position after 33... Rfg7 34. Nfg4 hxg4 35. fxg4
It likes Qg6 followed by f3
After Qg6 there will be Bxh4!. Now gxh4 seals the position.
After 35... Qg6 36. Bxh4, Crystal3.1 wants to play : f3 37. Nxf3 gxh4 38. Nxh4 Qxe4 39. Qxe4 Nxe4 with an eval around -2
After

37. Nxf3 gxh4 38. Nxh4 Qxe4 39. Qxe4 Nxe4 40. Nf5 Bxf5 41. Rxf5 Bg5 42. g3
I get a eval less then 1.00 after deep analysis.
Always Expect the Unexpected

Vinvin
Posts: 5009
Joined: Thu Mar 09, 2006 8:40 am
Full name: Vincent Lejeune

Re: correspondence chess in the age of NNUE

Post by Vinvin » Thu Feb 11, 2021 10:22 pm

Master Om wrote:
Thu Feb 11, 2021 3:06 pm
Vinvin wrote:
Mon Feb 08, 2021 7:42 pm
Master Om wrote:
Mon Feb 08, 2021 4:17 pm
Vinvin wrote:
Wed Feb 03, 2021 11:45 pm
Here's the opinion (3 best moves) of Crystal3.1 about the position after 33... Rfg7 34. Nfg4 hxg4 35. fxg4
It likes Qg6 followed by f3

[d]6rk/pp1bb1r1/3p1n1q/PPpPp1p1/2P1PpPn/R6P/4B1PN/1Q2BRK1 b - - 0 35

Code: Select all

Crystal3.1-sse4-popcnt:
...
 29/48	04:03	1 311 698 851	5 378 724	-2,13	35. ... Qh7 36.Bxh4 Qxh4 37.Rf2 Ra8 38.Rf1 Bd8 39.Bf3 Nh7 40.Rf2 Qh6 41.Rfa2 Nf8 42.Ra1 Kg8 43.R1a2 Ng6 44.Kf2 Rb8 45.Kf1 Qh4 46.Ke2 Qh7 47.Ke1 Nh4 48.Kf1 Rf7 49.Qd3 Qh8 50.Qb1 Kg7 51.Qd3 Ng6 52.Qb1 Be7 53.Kg1 Bf6 54.Kf1 Nh4 55.Kf2 a6 56.b6
 29/52	04:03	1 311 698 851	5 378 724	-2,13	35. ... Ra8 36.Ra2 Bd8 37.Ra3 Ng6 38.Bf2 Qh7 39.Bf3 Nh4 40.Bxh4 Qxh4 41.Rf2 Nh7 42.Rf1 Nf8 43.Rf2 Ng6 44.Rfa2 Kg8 45.Rb2 Qh6 46.Rba2 Rb8 47.Kf1 Qh4 48.Ke2 Qh7 49.Ke1 Nh4 50.Kf1 Rf7 51.Qd3 Qh8 52.Qb1 Kg7 53.Qd3 Ng6 54.Qb1 Be7 55.Kg1 Bf6 56.Kf1 Nh4 57.Kf2 a6 58.b6
 29/47	04:03	1 311 698 851	5 378 724	-2,35	35. ... Qg6 36.Ra2 f3 37.Nxf3 Qxe4 38.Qxe4 Nxe4 39.Nh2 Ng6 40.g3 Nf6 41.Bc3 Rf8 42.Nf3 Kg8 43.Kg2 Bd8 44.Bb2 Nh8 45.a6 b6 46.Nd2 e4 47.Ra3 Rgf7 48.Rb3 Re8 49.Re3 Rff8 50.Bd1 Ng6 51.Bc2 Ne5 52.Ba1 Re7 53.Bb2 Be8 54.Bxe5 Rxe5
Here's the opinion (3 best moves) of Crystal3.1 about the position after 33... Rfg7 34. Nfg4 hxg4 35. fxg4
It likes Qg6 followed by f3
After Qg6 there will be Bxh4!. Now gxh4 seals the position.
After 35... Qg6 36. Bxh4, Crystal3.1 wants to play : f3 37. Nxf3 gxh4 38. Nxh4 Qxe4 39. Qxe4 Nxe4 with an eval around -2
After

37. Nxf3 gxh4 38. Nxh4 Qxe4 39. Qxe4 Nxe4 40. Nf5 Bxf5 41. Rxf5 Bg5 42. g3
I get a eval less then 1.00 after deep analysis.
After your line, Crystal got -3.00. Which engine(s) do you use ?

Code: Select all

FEN: 6rk/pp4r1/3p4/PPpPpRb1/2P1n1P1/R5PP/4B3/6K1 b - - 0 42

Crystal3.1-sse4-popcnt:
...
 41/70	4:16:05	82 149 166 199	5 346 450	-2,22	42. ... Re8 43.h4 Bc1 44.Rb3 Nd2 45.Rc3 Bb2 46.Rc2 Bd4+ 47.Kg2 Nb3 48.g5 e4 49.Bh5 Ree7 50.Rf6 Rh7 51.Re6 e3 52.a6 bxa6 53.bxa6 Nd2 54.Rc1 Rxe6 55.dxe6 Re7 56.Bg4 Kg8 57.h5 e2 58.Re1 Be3 59.g6 Bg5 60.Bf5 Nxc4 61.Kf3 Ne3 62.g4 Nd5 63.Rxe2 Nc7 64.Rh2 Bf6 65.h6 Nxe6 66.h7+ Kh8 67.Rh6 Nd4+ 68.Kg2 c4 69.g5 Bxg5
 41/53	4:16:05	82 149 166 199	5 346 450	-2,85	42. ... Rb8 43.Kg2 Bd2 44.Rd3 Bxa5 45.Re3 Nc3 46.Bd3 e4 47.Bxe4 Nxe4 48.Rxe4 Bc3 49.Re3 Bd4 50.Ra3 a6 51.b6 Re8 52.g5 Re5 53.Rxe5 dxe5 54.Rf3 Kg8 55.Rf6 Rxg5 56.d6 Rg7 57.Re6 Kf8 58.h4 a5 59.h5 Rd7 60.h6 Kf7 61.h7
 41/83	4:16:05	82 149 166 199	5 346 450	-3,00	42. ... Rd8 43.Kg2 Bd2 44.Ra2 Be3 45.Rc2 Bd4 46.Bd3 Nc3 47.Rh5+ Kg8 48.Bf5 e4 49.Rc1 e3 50.Re1 a6 51.b6 e2 52.Be6+ Kf8 53.h4 Ke7 54.Bf5 Be3 55.g5 Bd2 56.Kf2 Re8 57.Rh6 Kf8 58.Be6 Rf7+ 59.Bxf7 Nd1+ 60.Kg2 Bxe1 61.Bxe8 Bc3 62.Re6 e1Q 63.Rxe1 Bxe1 64.Bb5 Bxa5 65.Bxa6 bxa6 66.b7 Bc7 67.Kf3 Nb2 68.Kg4 Nxc4 69.h5 Ne5+ 70.Kf5 Kg8 71.h6 c4 72.g4 c3

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